The future of grain legumes in cropping systems

Grain legume production is increasing worldwide due to their use directly as human food, feed for animals, and industrial demands. Further, grain legumes have the ability to enhance the levels of nitrogen and phosphorus in cropping systems. Considering the increasing needs for human consumption of plant products and the economic constraints of applying fertiliser on cereal crops, we envision a greater role for grain legumes in cropping systems, especially in regions where accessibility and affordability of fertiliser is an issue. However, for several reasons the role of grain legumes in cropping systems has often received less emphasis than cereals. In this review, we discuss four major issues in increasing grain legume productivity and their role in overall crop production: (i) increased symbiotic nitrogen fixation capacity, (ii) increased phosphorus recovery from the soil, (iii) overcoming grain legume yield limitations, and (iv) cropping systems to take advantage of the multi-dimensional benefits of grain legumes.